My tach was at 7000k. the speedo was way past the 140 mph mark, and I will add it was in the 70's (70 Deg F). I don't know if that helped any. I redlined every gear, when I got to 5th I just put my foot down as hard as I can get. And actually, I had recently replaced the speedo gears and took the car to get calibrated. I was 3 miles over. My Garmin was new and was put to the test with a buddies car. So plus or minus 3 miles an hour, She was about 152.